Introduction The legislative requirements to reduce the CO2 emissions from cars in Europe??for example@ by the European Commission setting a target to reduce CO2 emissions to 130 g/km for new 2012 vehicles with an inertia class of 1372 kg and a target of 95 g/km for similar inertia class by 2020?? have resulted in signi cant efforts by car manufacturers to explore various methods of reducing emissions from gasoline engines. Similar targets have been implemented worldwide@ including regulations to continuously reduce vehicle average eet fuel consumption in the United States over the next decade. One of the most effective means of achieving this reduction is by reducing the cylinder stroke or downsizing the engine. Typically@ 40% downsizing can result in about 20% reduction in fuel consumption. The full load torque of the original engine can only be recovered in the downsized engine by boosting the engine. However@ a boosted downsized engine can match the torque of an original engine at medium and high-speed conditions@ but there can be a de nite torque de cit at low speeds due to the limitations on the turbocharger ow range. To improve the drivability of highly downsized engines@ new concepts in turbocharging of gasoline engines need to be developed. In this book@ a number of the options currently being explored will be highlighted. The main topics to be considered are two-stage turbocharging@ compressor range extension methodologies@ unconventional compressor con gurations@ and electrically assisted turbocharging.
SAE PT-156-2014 history
2014SAE PT-156-2014 Concepts in Turbocharging for Improved Efficiency and Emissions Reduction